From 6033cf88a7971e27ba95233cd82f36be55dfc769 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Fri, 16 Dec 2016 06:56:39 +0100 Subject: hashtables: use counter and int to ensure forward progress Signed-off-by: Jason A. Donenfeld --- src/hashtables.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) (limited to 'src/hashtables.c') diff --git a/src/hashtables.c b/src/hashtables.c index 45c9737..534ad55 100644 --- a/src/hashtables.c +++ b/src/hashtables.c @@ -65,16 +65,10 @@ void index_hashtable_init(struct index_hashtable *table) spin_lock_init(&table->lock); } -#if BITS_PER_LONG == 64 -#define get_random_u64() get_random_long() -#else -#define get_random_u64() (((u64)get_random_int() << 32) | get_random_int()) -#endif - __le32 index_hashtable_insert(struct index_hashtable *table, struct index_hashtable_entry *entry) { struct index_hashtable_entry *existing_entry; - u64 rand; + u32 counter = get_random_int(); spin_lock(&table->lock); hlist_del_init_rcu(&entry->index_hash); @@ -84,8 +78,7 @@ __le32 index_hashtable_insert(struct index_hashtable *table, struct index_hashta search_unused_slot: /* First we try to find an unused slot, randomly, while unlocked. */ - rand = get_random_u64(); - entry->index = (__force __le32)siphash_1u64(rand, table->key); + entry->index = (__force __le32)siphash_2u32(get_random_int(), counter++, table->key); hlist_for_each_entry_rcu(existing_entry, index_bucket(table, entry->index), index_hash) { if (existing_entry->index == entry->index) goto search_unused_slot; /* If it's already in use, we continue searching. */ -- cgit v1.2.3